<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    *{padding: 0;margin: 0;}
    .content{
      /* width: 90%;
      max-width: 800px;
      height: 1000px;
      text-align: center;
      background-color: blue;
      margin: 0 auto; */
      /* 4 */
      /* width: 90%;
      max-width: 800px; */
      height: 100px;
      width: 700px;
      background-color: blue;
      position: absolute;
      /* left: 0;
      right: 0;
      top: 0;
      bottom: 0;
      margin: auto auto; */
      left: 50%;
      top: 50%;
      margin-left:-350px ;
      margin-top: -50px;
    }
  </style>
</head>
<body>
  <!--
    1.基础的行布局
    2.行布局自适应
    3.行布局自适应限制最大宽
    4.行布局垂直水平居中
  -->
  <div class="content">
    这是页面的基本内容
  </div>
</body>
</html>